André Villas-Boas spoke tentatively of his team's luck having turned. A third successive victory hinted at positive consistency and had been watched by Gary Cahill, a £7m arrival from Bolton Wanderers, in the stands. There was encouragement, too, to be drawn from Michael Essien's first appearance this term, the Ghanaian restored more speedily than had been anticipated after a knee ligament injury. Yet the biggest fillip to propel Chelsea's pursuit of the top trio was actually provided by the £50m forward who has now not managed a league goal in 114 days.

Statistics do Fernando Torres few favours these days, yet they belie the reality that the Spaniard is stirring again. This was arguably his most threatening performance in a Chelsea shirt, a display mustered as the anniversary of his British record arrival from Liverpool edges ever closer. Confidence is creeping back into his play at last. A fourth start in five matches has offered the 27-year-old rhythm that should be maintained while Didier Drogba is absent at the Africa Cup of Nations.

His movement on Saturday disconcerted Sunderland's defenders, unsettling full-backs and centre-halves alike. There was timing and majesty to admire in his 13th minute leap and volley to connect with Juan Mata's cross, and thrill to be had in his slippery dribbles into the penalty area. It sums up Torres's Chelsea career to date that a fine attempt thumped against the crossbar – albeit for Frank Lampard to convert the rebound – while the dart into the box and tumble under challenge saw him bizarrely booked for diving. "But he's willing to change his own fortune, and the goals will come," said Villas-Boas. "He's improving in form, confidence, he's looking better and creating danger. A goal may make a difference on a personal, inspiration level."

The drought in the league extends to the visit of Swansea City on 24 September when he scored and, with the adrenalin overflowing, was subsequently sent off for a wild lunge. Since then, the forward has been a provider rather than scorer. Saturday's was the 11th goal he has helped set up from open play, a startling record even if his instinct would be to convert rather than create those chances.

"As a striker I'm always trying to score and I always want to score," he said. "I'm hoping now I can find my best form again. It's been a different style here for me to adapt to and I've been giving assists for my team-mates, which has helped us towards winning games." Once conviction is fully restored, he can concentrate on being greedy again.

This contest was a tale of two strikers who could heavily influence the final months of this season and beyond. While Chelsea warm to positive signs from Torres, Sunderland can bask in the impact made by a forward who cost a fraction of the amount. James McClean, a £350,000 signing from Derry City last summer, has revelled when offered opportunity since Martin O'Neill's appointment and was watched here by Giovanni Trapattoni. The 22-year-old's enthusiasm might have been expected to shrivel when he skewered Sebastian Larsson's centre wide of a gaping goal. Instead, he recovered to tear into José Bosingwa with brutal relish on the flank. Such thick skin is needed in this unforgiving division.

The £18m Portugal defender wilted when confronted with McClean's raw ability. "It's not in James' nature to hide," said O'Neill. "He's beating himself up about the miss, but he's been fantastic for us. That was only his fourth start and he will be fine. Sometimes you have to teach him during the game, but he's so willing."

McClean will make waves on this evidence, whether or not he is selected for the Republic of Ireland's squad for Euro 2012. He will surely thrive under a manager relishing his own return to the limelight. O'Neill had grown weary of his involvement in football being restricted to watching DVDs of games from afar – "I know every player in the Peruvian league," he quipped – and seems such a natural fit on Wearside.

His team feel upwardly mobile again, even in the wake of this defeat. It was baffling how the visitors had failed to conjure an equaliser in the closing stages with the hosts clearly vulnerable and anxiety gripping those in the stands. Chelsea have shed too many points at home recently, which made this win feel all the more significant. Villas-Boas's manic celebrations at the final whistle were an outpouring of relief. O'Neill conceded they were "telling" of the way the game had headed.

"There's an obvious stigma around Stamford Bridge which is present for everybody to see," said Villas-Boas. "In the second half there was a tendency towards [nerves] because of recent happenings, but tension helps you concentrate." This team's focus remains.